Abstract
Brazil is the biggest orange producer in the world and processes about 85% of its production, generating a vast waste quantity. One of the components of these citric by-products is pectin, polymer of great interest to the food industry with possibilities to add value to these wastes. The objective of this study was to determine the optimum extraction conditions and characterize a value-added product, the citric pectin of lime orange waste produced in Santana do Mundaú city, Alagoas, Brazil. These conditions were evaluated through a 23 factorial design, with the acid concentration, temperature and extraction time as interest variables and the yield extraction and the esterification degree as answers. Texture analysis and compression profile were also performed. The lime orange residue was dried for about 18 hours, with removal around 80% of moisture, presenting high carbohydrate content (80%) and 8% of pectin. In the experimental conditions studied, it was noticed that at higher heating time (90 min), acid concentration (6%) and temperature (90 °C) it was obtained the highest yield of pectin extraction, around 78 %, with an esterification degree of 8%, that indicates a low degree of pectin methoxylation. While in the highest conditions were generated low pectin content, in low income were obtained high pectin methoxylation. A reason for this esterification loss was the high acid concentrations used, associated with longer heating times. In the texture profile analysis and compression, it was found that the extracted pectins possessed similar characteristics to the commercial one, especially in friability, hardness and elasticity aspects. When grinding, the pectin lost most part of these characteristics, assimilating to a standard without pectin.
